Trimec for spot spraying

Does trimec lose its effectiveness if left mixed with water in a small sprayer for occasional spot spraying? I read the label and I didn't see anything about this but I thought I remember reading something about it here.

It might lose a small amount of efficacy but, the reason companies don't mention it is because any leftover pesticide for turf or ornamentals is to be used only for for that purpose. This is an attempt to limit miss-use or improper disposal. Use it at the rates it was designed for and, if ineffective, wait a appropriate amount of time and mix a new solution and treat again.